There is a “very real risk” of Britain facing a full-blown outbreak of the bluetongue livestock virus, chief vet Debby Reynolds admitted tonight as a fifth case of the disease was confirmed in Suffolk.

There is a “very real risk” of Britain facing a full-blown outbreak of the bluetongue livestock virus, chief vet Debby Reynolds admitted last night as a fifth case of the disease was confirmed in Suffolk.

Ms Reynolds urged farmers to check the health of their livestock twice a day and confirmed that an animal had now tested positive for the midge-borne disease at a farm at Burstall, near Ipswich, and is to be culled.

The fifth case comes amid growing concern among farmers about animal welfare as Defra has imposed a ban on farm-to-farm movements in Norfolk and Suffolk.

A temporary surveillance zone stretching from the Home Counties to the East Midlands has been imposed where farmers are on alert for the disease.

Defra has now sent information about the five confirmed cases to the World Organisation for Animal Health - and said that tests were continuing to see how far the virus - which has a mortality rate of 70pc in sheep - might be circulating among animals and midges.

Britain's first two cases of the disease - which has seen 4,000 animals culled this summer in northern Europe - was confirmed at a rare breeds farm at Baylham, near Suffolk.

Defra said the relaxation of the current foot-and-mouth restrictions would be subject to “stringent' biosecurity measures, and stressed that the current control measures in the foot-and-mouth risk area remain in place.

Environment Secretary Hilary Benn said: “We have always taken a risk-based and staged approach to movement restrictions.

“The decision to announce today that livestock markets will be allowed from next Thursday follows extensive discussion with stakeholders, and I know will be of great benefit to the farming and food chain industry in easing economic and

welfare pressures.

“It will also allow time for preparations for markets to take place and for the required biosecurity measures to be applied.”

Following negative laboratory results, the foot-and-mouth disease temporary control zone in the Maidenhead area of Berkshire has also been lifted.

Laboratory tests show that the strain of foot-and-mouth found on the seventh infected premises is the same strain as that found on other premises in Surrey.

Meanwhile, investigations are ongoing in an attempt to establish whether bluetongue disease is circulating between animals and midges in the UK.

The disease is spread by biting insects.

A third case was found at a dairy farm at Lound, near Lowestoft, and the fourth at Copdock.

Ms Reynolds said: “Obviously, we must face the very real risk that bluetongue could already be actively circulating in this country. “It will be some time before we have the scientific evidence to confirm whether or not this is the case.

“Meanwhile as soon as the first bluetongue case was confirmed on Saturday, we have taken all the necessary measures on a precautionary basis. While our investigations continue it remains essential for animal keepers to, remain vigilant for disease and report any suspicions immediately. Livestock owners should examine their animals twice a day."

Ironically, the latest case came as the government lifted foot-and-mouth livestock movement restrictions in many other parts of the country.